1.3 Environmental Compliance, SDWA, Clean Water Act & NPDES Permits

1.3 Environmental Compliance, SDWA, Clean Water Act & NPDES Permits

Water and wastewater operators stand as the primary technical guardians between community public health and environmental degradation. To function effectively, operators must master the dual federal statutory structures that govern their facilities: the Safe Drinking Water Act (SDWA), which controls potable water from source to consumer tap, and the Clean Water Act (CWA), which controls wastewater discharges into state and federal receiving streams. In Alabama, primacy for both statutes is executed by ADEM through Administrative Code Division 335-7 (Public Water Supply Systems) and Division 335-6 (Water Quality Program).

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The Dual Federal Statutory Framework: SDWA vs. Clean Water Act

While water treatment and wastewater treatment share fundamental physical, chemical, and biological principles, their regulatory philosophies stem from distinct congressional mandates:

• Safe Drinking Water Act (SDWA) (Enacted 1974; amended 1986, 1996): Focuses exclusively on public drinking water systems supplying water for human consumption. It establishes mandatory, legally enforceable health standards for finished water quality, defines chemical and microbiological monitoring frequencies, regulates treatment techniques, and mandates customer public notifications.
• Clean Water Act (CWA) (Enacted 1972; amended 1977, 1987): Focuses on restoring and maintaining the chemical, physical, and biological integrity of the nation's waters. It makes it unlawful to discharge any pollutant from a point source into navigable waters without a specific permit issued under the National Pollutant Discharge Elimination System (NPDES).

                                  FEDERAL STATUTES
                                         │
                    ┌────────────────────┴────────────────────┐
                    ▼                                         ▼
     Safe Drinking Water Act (SDWA)                 Clean Water Act (CWA)
          42 U.S.C. § 300f                           33 U.S.C. § 1251
                    │                                         │
                    ▼                                         ▼
     ADEM Administrative Code                      ADEM Administrative Code
         Division 335-7                                 Division 335-6
   (Public Water Supply Systems)                  (Water Quality / NPDES)
                    │                                         │
        ┌───────────┴───────────┐                 ┌───────────┴───────────┐
        ▼                       ▼                 ▼                       ▼
Primary Standards      Secondary Standards    Effluent Limits         SSO & Bypass
  (MCLs & TTs)               (SMCLs)            (BOD / TSS)             Reports
(Health Enforceable)   (Aesthetic Quality)   (eDMR Submission)    (24-Hr / 5-Day Rules)

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Safe Drinking Water Act: Primary vs. Secondary Standards

Under ADEM Division 335-7, drinking water standards are bifurcated into Primary and Secondary categories:

1. National Primary Drinking Water Regulations (NPDWRs)

Primary standards are legally enforceable federal and state health standards that apply to all public water systems. They are designed to protect human consumers from acute and chronic health hazards:

• Maximum Contaminant Level Goal (MCLG): The non-enforceable level of a contaminant in drinking water below which there is no known or expected risk to health, allowing an adequate margin of safety. For known carcinogens and microbiological pathogens (Giardia lamblia, Cryptosporidium, Legionella, and E. coli), the MCLG is set strictly at zero.
• Maximum Contaminant Level (MCL): The highest permissible level of a contaminant in water delivered to any user of a public water system. MCLs are enforceable standards set as close to MCLGs as technically and economically feasible using the best available treatment technology (BAT).
• Treatment Technique (TT): An enforceable procedure or performance standard that public water systems must follow when it is not technically or economically feasible to measure the contaminant directly at extremely low concentrations. Examples include the Surface Water Treatment Rule (SWTR) requiring filtration and disinfection to achieve $99.9\%$ (3-log) removal/inactivation of Giardia and $99.99\%$ (4-log) inactivation of viruses, and the Lead and Copper Rule (LCR) requiring corrosion control optimization rather than a pure raw water MCL.

2. National Secondary Drinking Water Regulations (NSDWRs)

Secondary standards are guidelines established to regulate aesthetic qualities of drinking water—such as taste, odor, color, staining of fixtures, and foaming. Contaminants with Secondary Maximum Contaminant Levels (SMCLs) do not present direct health risks at standard concentrations:

• Iron (Fe): $\text{SMCL} = 0.3\text{ mg/L}$ (causes reddish-brown staining on laundry and porcelain fixtures; metallic taste).
• Manganese (Mn): $\text{SMCL} = 0.05\text{ mg/L}$ (causes black staining, bitter metallic taste, and distribution system sediment).
• Total Dissolved Solids (TDS): $\text{SMCL} = 500\text{ mg/L}$ (causes scale deposits, hardness, and mineralization taste).
• pH Range: $\text{SMCL} = 6.5\text{ to }8.5\text{ s.u.}$ (prevents distribution corrosivity or mineral encrustation).

Alabama Note: Although federal secondary standards are not federally enforceable, ADEM's groundwater rule (ADEM Admin. Code r. 335-7-5-.16) requires community and NTNC treatment facilities to be built to provide water meeting all primary and secondary drinking water standards, and Rule 335-7-10-.03 requires daily raw and finished iron and manganese tests whenever raw levels exceed the secondary limits.

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Clean Water Act & NPDES Permit Architecture

Under Section 402 of the Clean Water Act, every municipal wastewater treatment plant discharging treated effluent into an Alabama creek, river, lake, or bay must operate under an active National Pollutant Discharge Elimination System (NPDES) permit issued by ADEM.

NPDES permits establish binding parameters governing discharge volumes, pollutant concentrations, bioassay toxicity testing, and discharge monitoring schedules. Permits are issued for a fixed term not to exceed five (5) years.

Municipal Secondary Treatment Effluent Limitations

Title 40 of the Code of Federal Regulations (CFR) Part 133 sets the national secondary treatment standards (the BOD, TSS and pH rows below). Dissolved oxygen, bacteria and chlorine limits are set permit by permit by ADEM to protect the receiving stream's water quality standards, so those rows describe the form of the limits rather than fixed national numbers:

Percent Removal Mandate: Operators must remember that meeting the $30\text{ mg/L}$ concentration limit alone is not sufficient if influent sewage is dilute. The facility must demonstrate at least $85\%$ removal of $BOD_5$ and TSS from raw influent to final effluent over each calendar month:

$\%\text{ Removal} = \left( \frac{\text{Influent Concentration} - \text{Effluent Concentration}}{\text{Influent Concentration}} \right) \times 100$

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Discharge Monitoring Reports (DMR) & Electronic Reporting (eDMR)

Compliance with an NPDES permit is formally documented through the Discharge Monitoring Report (DMR):

• Electronic Submission (eDMR): ADEM mandates that all permitted facilities submit monthly monitoring data electronically using ADEM's secure online eDMR system.
• Filing Deadline: Under ADEM Admin. Code r. 335-6-6-.12, unless ADEM specifies otherwise, each DMR must be received by ADEM no later than the 28th day of the month following the reporting period (for example, January's DMR must be received by February 28).
• Chain-of-Custody & Certified Laboratories: All analytical data reported on a DMR must originate from test procedures approved under 40 CFR Part 136 (Guidelines Establishing Test Procedures for the Analysis of Pollutants). Utilities must maintain rigid chain-of-custody documentation, certified laboratory calibration logs, and bench sheets.
• Legal Certification Statement: The DMR must be signed by a responsible official or a duly authorized representative under the permit's certification statement, which acknowledges that false reporting or tampering with monitoring data carries federal and state criminal penalties.

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Sanitary Sewer Overflows (SSOs), Bypasses & Noncompliance Reporting

A sanitary sewer overflow (SSO) is a release of untreated or partially treated wastewater from the collection system (a manhole, cleanout, lift station or broken pipe) before it reaches the treatment plant. A bypass is the intentional diversion of waste streams from any portion of a treatment facility.

ADEM's NPDES rule, ADEM Admin. Code r. 335-6-6-.12, sets the reporting steps:

1. 24-hour report. Report to ADEM within 24 hours of becoming aware of any noncompliance that may endanger health or the environment. This includes violations of discharge limits the permit identifies for 24-hour reporting and any unpermitted direct or indirect discharge to a water of the state, regardless of cause.
2. 5-day written report. Submit a written report no later than 5 days after becoming aware. Reports for SSOs, combined sewer overflows and bypasses must be submitted electronically (required since December 21, 2020).
3. Report contents. Description of the noncompliance and its cause; exact dates and times (or how long it is expected to continue); steps taken to reduce, eliminate and prevent recurrence; and, for overflows and bypasses, the type of event, the type of overflow structure, the volume discharged untreated, the human health and environmental impacts and whether the event was related to wet weather.
4. Notifiable SSO. An overflow that reaches a surface water of the state or may imminently and substantially endanger human health (for example, near water supply wells or where people may contact it) must be reported as soon as possible to ADEM, the public, the county health department and other affected entities such as public water systems.
5. Anticipated bypass. If a permittee knows in advance that it needs to bypass, it gives ADEM prior notice, if possible at least 10 days before the bypass.

Other noncompliance is reported with the next monitoring report. Section 9.3 covers field response to overflows and volume estimation.

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Safe Drinking Water Act Public Notification Tiers

When a public water system violates drinking water standards under ADEM Division 335-7, it must issue public notifications categorized into three distinct tiers based on the seriousness of the public health risk:

Tier 1: Immediate Hazard (Notice Within 24 Hours)

Reserved for violations that have significant potential to cause serious adverse health effects from short-term exposure. Notice must be delivered within 24 hours via broadcast television/radio, reverse 911, hand delivery, or continuous public website banners:

• Exceedance of the Maximum Contaminant Level for E. coli.
• Failure to test for E. coli when any repeat sample tests positive for total coliform.
• Occurrence of a waterborne disease outbreak.
• A turbidity violation that ADEM decides needs Tier 1 notice (or when the system fails to consult ADEM within 24 hours).
• A lead action level exceedance (Tier 1 since October 16, 2024, under the Lead and Copper Rule Revisions).
• A fecal indicator such as E. coli detected in a groundwater source sample under the Ground Water Rule.
• Exceedance of the maximum residual disinfectant level (MRDL) for chlorine dioxide in the distribution system.
• Nitrate ($10\text{ mg/L}$) or Nitrite ($1.0\text{ mg/L}$) acute MCL exceedance.

Tier 2: Non-Acute Health Risk (Notice Within 30 Days)

Applies to violations with potential to cause adverse health effects that are not considered immediate emergencies. Notice must be provided within 30 days through direct mail to all billing customers or newspaper publication:

• Exceedance of MCLs for chemical or radiological contaminants (e.g., TTHM or HAA5 locational running annual averages, arsenic).
• In Alabama, a distribution disinfectant residual outside ADEM's limits for more than four hours, which is a treatment technique violation requiring newspaper notice within 14 days (ADEM Admin. Code r. 335-7-10-.04).
• Failure to comply with an enforceable Treatment Technique (TT), such as conventional filtration performance criteria or corrosion control protocols.
• Failure to perform required monitoring when ADEM escalates the violation to Tier 2.

Tier 3: Operational & Monitoring Violations (Notice Within 1 Year)

Applies to standard operational, monitoring, testing, or reporting irregularities that do not pose a direct threat to public health. Notice must be provided within one year (frequently satisfied via inclusion in the annual Consumer Confidence Report [CCR] mailed to all water customers by July 1):

• Failure to collect scheduled distribution water quality monitoring samples on time.
• Failure to follow approved analytical test procedures.
• Operating under an approved regulatory variance or exemption.

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Statutory Record Retention Standards

ADEM Division 335-7 (Drinking Water) and Division 335-6 (Water Quality/NPDES) enforce strict mandatory retention periods during which utilities must preserve official analytical records, bench sheets, and compliance logs on-site for state inspection:

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Worked Regulatory Scenario: Wet-Weather Sanitary Sewer Overflow and NPDES Exceedance

The Operational Context

A severe tropical storm delivers $5.5\text{ inches}$ of rainfall over an 8-hour period across the City of Pine Creek. The sudden surge in stormwater generates catastrophic inflow and infiltration (I&I) throughout the city's aging collection network:

1. At 07:30 hours on Tuesday, utility crews discover raw wastewater surcharging from a sanitary sewer manhole adjacent to Mill Creek (a recreational state waterbody). The discharge flows directly into the stream.
2. At the wastewater treatment plant, influent flow peaks at $350\%$ of design capacity. The extreme hydraulic loading washes solids out of the secondary clarifiers, causing the daily effluent Total Suspended Solids (TSS) concentration to reach $54\text{ mg/L}$ (against an NPDES daily maximum limit of $45\text{ mg/L}$).
3. Crew members install an emergency bypass pump, clear debris, and halt the manhole overflow at 13:30 hours on Tuesday (total duration: 6 hours). Engineering calculations estimate the total unpermitted discharge volume at $45,000\text{ gallons}$.

TIMELINE OF INCIDENT & COMPLIANCE ACTIONS:

Tuesday 07:30  ───► Manhole Overflow Discovered (Mill Creek)
Tuesday 13:30  ───► Overflow Terminated (Duration: 6 hrs | Volume: 45,000 gal)
Wednesday 07:00 ──► 24-HOUR DEADLINE: Initial Notice Filed with ADEM
Sunday 23:59    ──► 5-DAY DEADLINE: Comprehensive Written Report Filed with ADEM
End of Month    ──► Monthly eDMR Filed with TSS Exceedance & Non-Compliance Report

Step-by-Step Regulatory Compliance Response

1. Immediate On-Site Containment & Public Protection:
   • Isolate the spill area, apply hydrated agricultural lime to neutralize surface pathogens around the surcharged manhole, and install caution tape.
   • Immediately erect official warning signs along public access trails bordering Mill Creek reading: "WARNING: Untreated Wastewater Discharge. Avoid Contact with Water."
   • As good practice (or as ADEM directs), collect stream samples upstream and downstream of the discharge point for dissolved oxygen, pH and E. coli.
2. Execution of the 24-Hour ADEM Notification (Step 1):
   • Because the overflow was discovered at 07:30 Tuesday, the utility has until 07:30 Wednesday to submit initial notice.
   • The certified operator in responsible charge reports to ADEM at 15:00 on Tuesday, giving the location, estimated volume ($45,000\text{ gal}$), receiving stream (Mill Creek) and containment status.
   • Because the sewage reached Mill Creek, this is a notifiable SSO: the utility must also notify the public, the county health department and any affected public water system as soon as possible.
3. Preparation & Submittal of the 5-Day Written Report (Step 2):
   • The utility must submit a full written report to ADEM within 5 days (by Sunday).
   • The written report includes: exact rainfall data ($5.5\text{ inches}$), hydraulic calculation methodologies used to derive the 45,000-gallon spill estimate, stream sampling data showing dissolved oxygen impact on Mill Creek, corrective maintenance completed, and a long-term capital improvement proposal to smoke-test and line the upstream gravity sewer collection basin.
4. Handling the Clarifier Washout NPDES Permit Exceedance:
   • The single-day TSS spike of $54\text{ mg/L}$ violates the daily maximum limit ($45\text{ mg/L}$).
   • The operator immediately records the exceedance on the daily operational log and flags the sample for the monthly eDMR.
   • The utility reports the exceedance and its cause with the monthly eDMR (received by ADEM by the 28th day of the following month), describing the storm, the clarifier washout and the corrective steps. If the permit lists TSS among parameters requiring 24-hour reporting, the exceedance must also be reported within 24 hours.
5. Archiving & Retention Compliance:
   • All stream lab bench sheets, overflow logs, rainfall charts, and copies of the 5-day report are placed in the permanent compliance file and retained for at least 3 years under ADEM's NPDES rule (longer if ADEM requests it or enforcement is pending).